High efficiency external daylighting devices

ABSTRACT

A external light control device for equatorially located building utilizes tilting external light shelves that are capable of tilting backward (toward the building) from a vertical orientation to reflect low am (or late pm) sun away from occupants, but are deployed at a tilt away from the building exterior to capture more sun closer to noon time. The structure preferably integrate IR rejecting coating for incident light which is re-directed by TIR surface disposed normal to the thin film layers in a multi-layer IR reflective coating. The panel may be monolithic or comprise tilting louvers, which can be metallic, dielectric, or TIR reflectors. The louvers preferably also tilt in response to the determined sun position with the panel to optimize light utilization.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of priority the USProvisional Patent application of the same title, which was filed onApr. 29, 2016, having application Ser. No. 62/329,607 and isincorporated herein by reference.

BACKGROUND OF INVENTION

The field of invention is building construction, and more specificallyexterior optical assemblies for directing light into buildings.

It has long been recognized that various optical components placed onthe exterior of buildings can capture external light and transmit it tothe interior of a building through glazing structures. Such structureshave been incorporated on rooftops to increase the efficiency ofskylights, as well as over external side wall glazing to captureexterior sunlight.

Such structures have typically been various types of mirrors that merelyre-directly the light into the interior.

There has always been a tradeoff between the quantities of lightcaptured to minimize the undesirable effects of excess light, such asdirect glare to occupants, as well as the undesirable excess heat duringthe warmer seasons of the year.

It would be advantageous to provide a means to capture external lightand re-direct it in a manner that avoids glare or other forms of excessbrightness, as well as solar heating effects that is also dynamicallyresponsive to the changing solar elevation angle throughout the day.

The above and other objects, effects, features, and advantages of thepresent invention will become more apparent from the followingdescription of the embodiments thereof taken in conjunction with theaccompanying drawings.

SUMMARY OF INVENTION

In the present invention, the first object is achieved by providing anapparatus for exterior light control, the apparatus comprising a firstand second elongated supporting member, each being spaced apart from theother with the principle axis disposed parallel to define a first plane,one or more optical panel is attached at opposing sides to the each ofthe first and second elongated supporting member, a pair of pivotingbrackets, each bracket having; a means for vertical surface mounting toa second plane; and connecting opposing sides of the panel foradjustably disposing the first plane between a positive and negativeorientation with respect to a second plane.

A second aspect of the invention is characterized by a buildingstructure comprising a plurality of exterior vertical walls, at leastone wall having at least one penetration covered by a glazing panel, theapparatus for exterior light control of claim 1 attached to the exteriorwall by the pivoting brackets and disposing the first plane between apositive and negative orientation with respect to at least one wall asthe second plane.

In the present invention, the first object is achieved by providing anapparatus for exterior light control, the apparatus comprising a firstand second elongated supporting member, each being spaced apart from theother with a principle axis of each member having a portion disposed inthe same direction as the other define a first plane, one or more planaroptical panels attached at an opposing sides to the each of the firstand second elongated supporting member to each portion to dispose theplanar optical panel in the first plane. a pair of pivoting brackets,each bracket having; a means for vertical surface mounting to a secondplane; and a pivoting coupling to the first and second elongatedsupporting members that is operative for adjustably disposing the planaroptical panel between a positive and negative orientation with respectto a second plane, wherein the planar optical panels comprise aplurality of reflective elements that are operative to redirect incidentlight via transmission through the planar optical panel toward thesecond plane.

A second aspect of the invention is characterized such an apparatusexterior light control wherein the reflective optical elements re-directlight by total internal reflection.

Another aspect of the invention is characterized by any such anapparatus for exterior light control wherein the reflective opticalelements re-direct light by total internal reflection and have aperiodic pitch that is greater than at least about 500 microns.

Another aspect of the invention is characterized by any such anapparatus for exterior light control wherein the optical panel comprisesa plurality of louvers.

Another aspect of the invention is characterized by any such anapparatus for exterior light control wherein the pivot brackets areconnected at opposing sides of the planar optical panel at a mid-pointbetween each of the first and second elongated supporting members.

Another aspect of the invention is characterized by any such anapparatus for exterior light control wherein the pivot brackets have alength that is greater than half the length of the first and secondelongated supporting members for rotating the one or more optical panelsfrom an upright to an inverted position without contacting the secondplane.

Another aspect of the invention is characterized by any such anapparatus for exterior light control wherein the louvers comprise alight re-directing optical panel that is disposed between two IRreflective layers on opposing sides and the light redirecting opticalpanel is operative to absorb light incident at a direction above anormal direction in a first orientation and re-direct light incident ata direction above a normal direction in a second orientation in whichthe louvers are inverted from the first orientation.

Another aspect of the invention is characterized by any such anapparatus for exterior light control wherein the louvers comprise alight re-directing optical panel that is disposed between two IRreflective layers on opposing sides and the light redirecting opticalpanel.

Another aspect of the invention is characterized by any such anapparatus for exterior light control wherein the louvers comprise aplurality of alternating bands of adjacent plano see-through regions andlight redirecting regions wherein the bands extend in the direction ofthe louvers and transverse to the elongated supporting members.

Another aspect of the invention is characterized by such an apparatusfor light control wherein the louvers are disposed with a primary axisthat extends in the same direction as the first and second elongatedsupporting members and the louvers are coupled to the first and secondsupporting elongated members to rotate about the primary axis.

Another aspect of the invention is characterized by any such anapparatus for exterior light control wherein the louvers are operativeto be independently rotated about a primary axis independent of apivoting movement of the planar optical panel between a positive andnegative orientation with respect to a second plane.

Another aspect of the invention is characterized by any such anapparatus for exterior light control further comprising a means toreflect infrared radiation.

Another aspect of the invention is characterized by any such anapparatus for exterior light control further comprising a means forrotation of the pair of pivoting bracket about an axis that is disposednormal to the second plane and midway between the pivoting brackets.

Another aspect of the invention is characterized by any such anapparatus for exterior light control further comprising a control systemthat is operative to pivot the one or more planar optical panels tofollow a trajectory of the sun.

Another aspect of the invention is characterized by any such anapparatus for exterior light control further comprising a control systemthat is operative to pivot the louver and the one or more planar opticalpanels to follow a trajectory of the sun.

Another aspect of the invention is characterized by any such anapparatus for exterior light control further comprising a control systemthat is operative to pivot the one or more planar optical panels tofollow a trajectory of the sun.

Another aspect of the invention is characterized by an optical componentcomprising a plurality of alternating bands of adjacent; planarsee-through regions and light redirecting regions in which the lightre-directing regions are transparent and re-direct light by totalinternal reflection, in which the planar see-through regions are widerthan the spacing of adjacent light redirect elements in the lightre-directing regions.

Another aspect of the invention is characterized by any such opticalcomponent wherein the light re-directing regions have a plurality offacets that are disposed at an oblique angle with respect to the planarsee-through regions.

Another aspect of the invention is characterized by any such opticalcomponent wherein the planar see-through regions attenuate incidentlight by absorption.

Another aspect of the invention is characterized by any such opticalcomponent further comprising a means for reflecting infrared radiation.

Another aspect of the invention characterized by any such opticalcomponent wherein the planar see through region are disposed above a topof the plurality of facets.

Another aspect of the invention is characterized by any such opticalcomponent wherein the planar see through region are attached to a planartransparent optical panel to provide a gap between the facets of thelight re-directing regions.

Another aspect of the invention is characterized by any such opticalcomponent wherein an infrared radiation reflective layered structure isdisposed between the planar transparent optical panel and the lightre-directing regions by attaching the planar see-through regions to theinfrared radiation reflective layered structure.

Another aspect of the invention is characterized by a building structurecomprising a plurality of exterior vertical walls, at least one wallhaving at least one penetration covered by a glazing panel, theapparatus for exterior light control of claim 1 attached to the exteriorwall by the pivoting brackets and disposing the first plane between apositive and negative orientation with respect to at least one wall asthe second plane. The above and other objects, effects, features, andadvantages of the present invention will become more apparent from thefollowing description of the embodiments thereof taken in conjunctionwith the accompanying drawings.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a plot of the Fresnel reflection coefficients as a function ofangle of incidence.

FIG. 2 is a plot of projected areas as a function of angle of incidence.

FIG. 3 is a schematic side elevation view of a first embodiment of theinvention with the frame tilted away from window and building.

FIG. 4 is a schematic side elevation view of a first embodiment of theinvention with the frame in vertical orientation and the optionalnegative tilt orientation.

FIG. 5 is a schematic perspective view of the another embodiment of theinvention.

FIG. 6 is a schematic perspective view of another embodiment of theinvention.

FIG. 7A-C are schematic side elevation views comparing differentembodiments of the invention.

FIGS. 8A and 8B are cross sectional elevation views of the embodiment ofFIG. 5-7 that includes ray tracings showing the penetration of the solarradiation into a room.

FIG. 9 is a cross sectional elevation view of another embodiment of theinvention showing the configurations of the light re-directing frame formultiple floors in a building and includes ray tracings showing thepropagation of solar radiation into a room on each of the adjacentfloors.

FIG. 10 is a schematic perspective view of another embodiment of theinvention showing a control and actuation system for titling the framein response to the solar elevation.

FIG. 11 is a schematic perspective view of another embodiment of theinvention showing a control and actuation system for tilting the framein response to the solar elevation.

FIG. 12 is a schematic perspective view of another embodiment of theinvention showing a control and actuation system for tilting the framein response to the solar elevation.

FIG. 13 is perspective view of a portion of a tiltable louver.

FIG. 14 is a cross-sectional elevation of a portion of an alternativeembodiment of the louver in FIG. 12.

FIG. 15 is a cross-sectional elevation of a portion of anotheralternative embodiment of the louver in FIG. 12.

FIGS. 16A and 16B are schematic cross-sectional elevation view ofportions of alternative embodiment of the louver in FIG. 1.

FIG. 17 is the cross-sectional elevations of the portion of thealternative embodiment of the louver assembly of FIG. 16 when invertedin the frame to block the visible and IR components of sunlight, whilestill allowing see-through visibility from the inside of the building.

FIGS. 18A and 18B are cross-sectional elevations of a portion of thealternative embodiment of the louver.

FIG. 19 is a cross-sectional elevation view of an alternative embodimentof an optical re-directing element supported by the frame.

FIGS. 20A and 20B are front and side elevation view of an alternativeembodiment of a louver or panel.

FIGS. 21A and 20B are alternative embodiment of a louver or panel.

FIG. 22 is a side elevation view of an alternative embodiment of a lightre-directing louver system that rejects IR radiation.

FIGS. 23A and 23B are front and side elevation view of anotherembodiment of the frame having elongated upright louvers disposed torotate about an axis orthogonal to the rotation axis of the frame.

FIG. 24A-C are front elevation views of alternative positions of a framethat rotates about an addition axis to follow the arcing solartrajectory for optimal collection of solar radiation.

DETAILED DESCRIPTION

Referring to FIGS. 1 through 23C, wherein like reference numerals referto like components in the various views, there is illustrated therein anew and improved High Efficiency External Daylighting Devices, generallydenominated 1000 herein.

An objective of the invention is to provide daylighting constructionswith improved efficiency in geographic locations of low latitudes, from0 to 30 degrees, which is roughly latitudes equivalent to south ofnorthern Florida and north of southern Brazil in the Western hemisphereand Shanghai to Brisbane in the Eastern Hemisphere. In these latitudesthe sun spends significant time during the daily sun cycle at elevationangles above 60 degrees and especially above 70 degrees.

At high sun angles, daylighting efficiency is greatly diminished byFresnel reflection losses from vertical fenestrations and from cosinelosses of the glazing projected area.

In regard to the losses associated with Fresnel reflection on glazing ofn=1.5, FIG. 1 shows the rapidly increasing Fresnel reflectioncoefficients as a function of incidence angle and polarization.

Further, as illustrated in FIG. 2, at high solar elevation angles, theprojected area of glazing goes down by the cosine of the elevationangle. That is, the amount of daylight intercepted by a verticalfenestration goes down by the product of the window area and the cosineof the sun elevation angle, as shown in the plot below. This means thatthe projected window area is effectively “0” when the sun is at 90degrees elevation, as the cosine of 90 degrees is zero.

It is an object of the invention to provide for the more efficientutilization of sunlight for interior lighting when it is at highelevations, greater than about 65 degrees, but also to preclude or shadethe occupants from low angle sun that would be present as either glareor direct images of the solar disk at eye level. Glare should beunderstood to be areas of high brightness that would be visible when aninternal observer or room occupants looks outward to a window 15.

It has been discovered that improvements are preferably obtained byproviding light re-directing components externally to buildingstructures to increase the projected area and decrease the incidenceangle to significantly increase the amount of available daylight thatcan be re-directed in a useful manner by preferred embodiment of theseexternal constructions.

It should be appreciated that since the inventive structure and devicesdescribed in further details below can be deposed between the roomintended to receive enhanced illumination from exterior light, whichincludes sunlight, and the source of the exterior light, the terms“exterior”, “external” and “externally” are also intended to embraceapplications to rooms or floor space portions without windows, such asin indoor atriums, that for example have skylight windows. According,exterior means a placement of the device between the room or space thatis intended to receive enhanced illumination from a light source distalfrom the room or space when the apparatus is placed between the room orspace and the lighting source. For simplicity, most embodiments will bedescribed with respect to the sun being the source of illumination androom or space being an interior of the building in which opening arecovered by window glazing.

The preferred embodiments of these improved constructions areimplemented on a macro level with respect to building structure as wellas at a micro-level of the optical element construction to optimize theperformance and versatility of the devices, as well as manage the issueof solar heating, which occurs year round at tropical latitudes, that isabout ±23 degree latitude.

In accordance with the various aspects of the present invention the HighEfficiency External Daylighting Devices 1000 is deployed on the exteriorvertical wall 17 of the building with a vertical exterior window orglazing 15. The device 1000 comprises a frame 1110 and one of moreoptical light redirecting elements 1124 of optical panel 1120 having atransmitting portion 1125 that is supported by the frame 1110 via acoupling pivot assembly 1130. The frame 1110 is coupled in rotaryengagement by the pivot assembly 1130 with the pivot assembly 1130 andthe frame 1110 being spaced away from a building outer or exterior wall17 by a laterally projecting stand-offs or brackets 1140. The stand-off1140 displaces the primary or pivot axis 1001 of the assembly 1130 andthe one of more optical light redirecting panel 1120 laterally away fromthe glazing 15. The frame 1110 to support the optical panel comprises atleast a first and second elongated supporting member, each being spacedapart from the other with a principle axis of each member having aportion disposed in the same direction as the other define a firstplane. The frame 1110 and elongated members can have various shape, butthe portion are provided in a configuration to dispose the planaroptical panel in the first plane so that it can be tilted with respectto an adjacent wall or window of a building that is in a second spacedapart plane. The optical light redirecting element 1120 can be one ormore planar optical panels attached at opposing sides to the each of thefirst and second elongated supporting member via such portions.

The pivot assembly 1130 may be operative to dispose the more opticalpanels redirecting 1120 and the light re-directing elements 1124 thereofat both positive (1120+ in FIG. 3) and negative tilt (1120− in FIG. 4)with respect to the vertical direction or the second plane, asillustrated in FIGS. 3 and 4, by rotation about a primary axis 1001defined by the pivot assembly 1130.

While a frame 1110 preferably has 3 or more sides, and preferably 4sides for strength and rigidity, the frame 1110 needs 2 sides orelongated members 1110 a and 1110 b (FIG. 6) to grasp the optical panel1120, which can be one formed from or more smaller rigid panels 1121 byassembly tiles. The optical panel 1120 can be formed as a monolith,laminate or by tiling in a common plan other elements or laminates, withother without intervening sub-frames. Alternatively louvers 600 can bestacked by attachment to the frame 1110. Louvers 600 may be have a fixedorientation with respect to the frame 1110, but preferably may pivot orrotate within the frame 1110.

Light re-directing films and sheets are well known and are generallyformed by micro-fabrication methods in which the total internalreflection (TIR) surfaces are less than about 1 mm wide. Suchmicro-fabrication typically deploys micro-replication of a mastersurface or mold in which a resin impregnates the contours of the mastersurface so that upon curing and removal the master surface is replicatedin reverse. The master surface is generally fabricated by diamondcutting or turning. Some micro-replication methods are well suited toroll to roll processing of wide webs of flexible films. A web offlexible film can be readily slit and cut to custom sizes, as may berequired for direct application to an installed window glazing surface,or the glass panel or plates used to fabricate sealed glazing typewindows. While in some embodiment the slat or louver 600 or opticalpanel 1120 that is supported by the frame 1110 may contain a continuouslayer of thin flexible film, in more preferred embodiments, the slat orlouver is a collection of assembled macro-elements to provide particularperformance advantages. FIG. 14-17 illustrate more preferred embodimentsthat deploy such macro-elements 110. By film, we mean a planar membergenerally less than several mm in thick and sufficiently non-rigid to berolled to a radius of about 12 mm with breakage, crazing or plasticdeformation. Films can be laminated to thicker members to form generallyrigid panels, when the thicker member itself provides 90% percent of therigidity. Films can be laminated with other films and less rigid membersto form more rigid structures as the optical panel 1120. The lightre-directing reflective surface 1124 can be formed by various methods,such as in either flexible film, more rigid member members, or laminatesthereof, in which the light re-directing reflective surfaces 1124 can beon the front, rear or embedded within such structure. Any of theseconstructions can be used to form an optical panel 1120, tiles used toform the optical panel or the louvers 600. By louver 600, we meanelongated flat members that are narrow with respect to the longest axisand very thin with respect the next longer or narrower dimension. Suchlouvers can be formed by tiling shorter louver forming optical elements.

In general, the light re-directing structure 1121 is disposed on or partof at least one of the opposing faces of the planar support to formeither the panel 1121 or the louver 600. Hence, at least a portion ofthe incident light will be selectively re-directed on transmissiondepending on the angle of incidence. In most embodiments, light at a lowangle of incidence when reflected after initial transmission isre-directed above the surface normal to travel in the opposite directionas the incident light, for entering the building through the adjacentwindow.

Preferably such light re-directing structure deploy multiple adjacentreflective surfaces 1124 oriented for the total internal reflection(TIR) of light impinging on the optical panel 1120 at a higher angle ofincidence above the surface normal to be re-directed and exit the panelbut also travel upward, but in the same direction as the incident light.Absent the TIR surface, all of the light will travel downward on exit anotherwise plano-plano transparent panel. As TIR only occurs above acritical angle of incidence dependent, replacing TIR with metallic ordielectric reflective surface, allows some portion of near normalincident light to be reflected as well.

It should be appreciated from the ray tracing in FIG. 3, showingincident sunlight as ray 10, as the frame 1110 swings lightingtransmitting element 1125+ away from the wall 17 to capture moresunlight, the light captured will be redirected as ray segment 11 atlower angles toward the occupants, and not at the higher angles towardthe ceiling 20, as is the case for ray segment 11′, which is associatedwith the vertical panel or frame 1110 supporting the light re-directingelement 1120. An aspect of the invention is the configuration and use toaddress the bothersome natural of low angle sunlight, for which frame1110 can be tilted in the negative direction, as shown in FIG. 4.

FIG. 4 is a schematic perspective view of an embodiment of the inventionshowing a frame 1110 that is essentially the same height as the windowdisposed for positive and negative tilt of the vertical orientation ofthe frame with respect to the wall 17, including ray tracing of incidentsunlight. The negative tilt (1120−) avoids the “leakage” of incidentlight 10 of near vertical light that does not impinge on the reflectivesurface in the light re-directing element 1124. This can occur when thelight re-directing elements 1124 have reflective surfaces (such as 110 aand 110 b in FIG. 14-17) that parallel to each other, and transverse tothe plane of the frame 1110. The optical panel 1120—of frame 1110 isdisposed at negative tilt to optimize the re-direction of low angleincident light, such as on due east or due west facing windows early inthe morning or late in the afternoon respectively. In such cases, it isdesirable that building occupants are not blinded by direct sunlight,but can still view the exterior landscape or skyline. This can beaccomplished different ways with various embodiments, though each waypresents some tradeoffs in different aspects of performance. The morepreferred embodiments deploy improved structure for the lightre-directing components, 1124, be they in the form of monolithic panelsof smaller panels or tiles 1121 that are fixed to the frame 1110 or anassembly of louvers 600 that can be rotated independent of the frame1110 rotation.

Further, at higher solar elevations low angle sun, incident as ray 10 at30 degrees elevation is re-directed to a higher angle toward the ceilingas ray 11, rather than ray 11′ which would occur if the frame 1110 andlight re-directing portion 1120 remained vertical. This redirection canbe accomplished by titling the frame 1110, or tilting the louvers 600 ina frame 1110 that remains vertical, or any combinations of tilting theframe 1110 and the louvers 600.

Further, as a larger angle of negative tilt re-directs the light at asteeper (or higher angle) into the room, that is toward the ceiling 20closer to the window 15, more negative tilt may be desired to protectoccupants from this direct light if they work or stand close to awindow.

The structure of the frame 1110 and stand-off 1140 can limit the extentof the negative tilt, when the bottom of elongated members 1110 a/b ofthe frame 1110 will hit the wall 17 or window 15. The support of theelongated members 110 a/b and the frame 1110 as illustrated in FIG. 7Aallows greater negative tilt for a given support length in the verticaldirection. The combination of negative tilt of the frame 1110 and thelouvers 600 provides greater negative tilt. However, tilting louvers 600may have some detrimental consequences, namely light leakage between TIRsurfaces or reflective surface in the light re-directing structure 1120.

FIGS. 5 and 6 illustrate respectively in perspective view that the frame1110 and light re-directing portion 1120 may be deployed over the entirevertical expanse of the window 15 (FIG. 5) or an upper or clerestoryportion (FIG. 6) 15 u of the window 15. As the clerestory portion 15 uis above the eye level of the occupants, it is more acceptable to deployoptical panel 1120 as shown in FIG. 3 in which the re-directed light 11at a lower angle than ray 11′.

FIG. 7A-C are schematic side elevation views comparing a second and thefirst embodiment of the invention in which the light re-directingelements 1120− are disposed with negative tilt. As illustrated in FIG.7A, the laterally projecting stand-off 1140 is supporting the frame 1110at the vertical center provide a greater negative tilt for the sameframe height at a given spacing away from the building 17 than the topframe mounted stand-offs 1140 in other embodiments.

As previously mentioned, another aspect of the inventive device 1000 isillustrated in FIG. 7C (as well as FIG. 10-12) in which a plurality ofplanar optical light re-directing elements 1120 supported by the frame1110 are louvers 600. While the frame 1100 is disposed in pivotingengagement with the pivot member 1130 on the end of the stand-off 1140to rotate about a primary axis 1001, each louver 600 is also operativeto rotate about a secondary axis 1002 at the point of the connection tothe frame 1110.

In general, the frame 1110 having the array of louvers 600 of FIG. 7Ccan be rotated out from the building and behave very similar to thesolid rotated panel. Deployment of frames 1110 with rotatable louvers600 as the light re-directing 1124 and transmitting portion 1125 of theoptical panel 1120 may have several advantages in particularconstructions. The louvers 600 provide some advantages to optimize thecapture of light to increase lighting efficiency, while also allowingthe captured light to be directed toward the ceiling, where the diffusescattering provides a more desirable interior ambiance.

One such advantage is that that the frame 1110 need not be rotated sofar from the window 15 to capture lights, as the angle of the lightre-redirection can be set by a combination of a lower frame rotation anda some rotation of the louvers. In the case of a multi-story buildingillustrated in FIG. 9, the stand-off 1140′ and 1140″ can be shorter whenthe upper frame 1110 rotation is reduced by a contribution from therotation of the louvers 600, as the lower edges of the frames 1110 b ofthe upper stories can have narrower projection away from the buildingwall 17 that would block sunlight from reaching the optical panel 1120and transparent portion 1125 in the frames 1110 disposed at windows inthe lower stories.

A general optimum range of frame 1110 and/or louver 600 tilt has beendiscovered for the inventive structure 1000 that provides a beneficialcompromise for increasing the efficiency of sun light utilization whileavoiding light leakage and other effects that produce undesired glare orinternal heating from the infrared components of sunlight. It isgenerally desired that the re-direction angles of ray 11, for theexternal structure 1000, to direct light to the center of a ceilingspace, range between 12 to 17 degrees. If re-direction is desiredfurther back into a room, the range is approximately 6 to 9 degrees. Insuch cases, taking into account efficiency over a range of solarelevation angles it is generally preferably to tilt the optical panel1120 or frame 1110 upward between about 20 to 40 degrees from thevertical orientation, but more preferably from about 25 to 35 degrees.

In the case of the optical panel 1120 deploying as light re-directingcomponents 1124 the parallel spaced apart TIR surface 110 a and 110 b inFIG. 14-17, the optimized extent of frame tilt or frame tilt and louver600 tilt is dependent upon the aspect ratio of the elements 110. Whenthe optical elements 110 a and 110 b have a 2:1 aspect ratio (width offace 110 a divided by vertical height) the efficiency of lightutilization is a maximum at a solar elevation is 42 degrees. It has beendiscovered that the optimal positive rotation of the optical panel 1120for high sun angles is 25 to 35 degrees for this 2:1 aspect ratio. Onthe other hand, for low sun angles, the panel 1120 will be tilted from10 to 30 degrees, negative, and is only limited by the buildinginterference and the acceptable lateral length of the stand-off orbrackets 1140.

Further, wind loading on the solid panel 1120 will be higher than thatof a louvered panel of the same size, due to the air gaps in betweenlouvers 600 providing channels for air to flow.

In more preferred embodiments the louvers 600 themselves can beindependently rotated, relative to each other, for re-directing lightover a programmed range to spread the light over a greater width of theceiling 20 in a building. This benefit is illustrated in FIG. 8, inwhich ray 11″ corresponding to the lowest louver 600 in the externalframe 1110 is at a lower elevation angle to penetrate further in theroom, scattering off the ceiling 20 as rays 12″.

It should be appreciated that disadvantages that may exist or bediscussed with some modes of operation or use do not apply to allembodiments. Notably, with respect to the embodiment of FIG. 6, in whichthe frame 1110 and optical panel 1120 is deployed only in a clerestoryposition, that is the portion of the window that is above eye level, itis not as important to direct light at steeper angles as the frameswings outward from the building to capture more light. With a lightre-directing structure in a clerestory position, any upward re-directionof sun light will avoid directing light into the eyes of a buildingoccupant.

It should also noted from FIG. 7A-C, that the potential combination oftilting the frame 1110 and the louvers 600 provides the greatest rangeof negative tilt for a fixed laterally projecting stand-off 1140 whilemitigating the straight through leakage of light. In contrast, when theoptical panel 1120 is a monolithic transmitting region 1125, as opposedto the assembly of louvers 600 in the frame 1110, the potential forlight leakage between louvers on negative rotation is avoided. However,depending on the optical design of the light re-directing elements 1124,straight through leakage for incidence angles below 40 degrees ispossible. For example, in the case of the 2:1 aspect ratio of theoptical elements 110 of FIG. 14-16 the angle above which there is noleakage is exactly at 42 degrees.

FIGS. 8A,B and 12 illustrate several aspects of using an external daylighting device 1000 of FIG. 7A to re-direct least some portion of solarlight rays 10 incident at higher angles with positive tilt of the frame1110. FIG. 8 is a cross sectional elevation view of the embodiment ofFIG. 12 that includes ray tracings showing the penetration of the solarradiation into a room toward the ceiling 20. Solar radiation incident athigh angles from the sun 10 on glazing 15 is re-directed by lightre-directing elements 1124 of optical panel 1120 away from the path 10′it would otherwise take in a room toward the floor 5, and re-directedback upward towards the ceiling 20 as ray 11. Thus, incident sunlight,is upon being re-directed, scattered off the ceiling 20 as rays 12,providing occupant farther from a window glazing 15 with diffusednatural light. The external light re-directing element can be deployedso different portions thereof are operative to spread the rays 11 acrossa desired portion of the ceiling 20 width, such as the lower portion ofthe optical panel 1120, which is optionally a rotatable louver 600″ toproject rays 11″ more distal from the window 15 to be diffused downwardas scattered rays 12″.

Alternatively as shown in FIG. 8B, the light redirecting element 1124 ofpanel 1120 can be disposed on a plurality louvers 600 that areselectively rotated to direct the light over a greater width of theceiling 20 while minimizing the potential for light to be-redirected atthe eyes of an inside occupant. Louver 600′ is tilted for re-directinglight 10 at the top of the frame 1110 toward the rear portion of theroom as ray 11′, that is the parts of the ceiling 20 most distal fromthe window 15, and the lowest louver 600″ in the frame re-directing thelight 10 at the steeper incident angle as ray 11″ closer to the window15, which scatters of the ceiling 20 as diffuse lighting rays 12″

FIG. 9 is a cross sectional elevation view of another embodiment of theinvention showing the configurations of the optical panel 1120 onstand-offs or brackets 1140, 1140′ and 1140″ respectively for multiplefloors 201, 202 and 203 in a building. FIG. 9 also includes ray tracingsshowing the propagation of direct downward solar radiation 10 into aroom on each of the adjacent floors, which scatters off the ceiling asrays 12. Each laterally projecting stand-off 1140 at successively lowerfloors extends farther away from the building wall 17 to capture nearlyvertical sunlight thus avoiding the effective shadowing caused by eachof the upper devices 1000. The lateral extension of the lowest standoff1140″ is sufficiently larger than the previous standoff 1140′ to accountfor the forward projection of the lower edge of the frame 1140′ and theoptical redirecting structure 1120 thereof. When the standoff 1140 ismounted to the vertical center of the frame 1140′, each successivelylower standoff needs to extend outward further to account for the rearward projection of the top of the frame 1110.

FIGS. 10 and 12 illustrate additional embodiments of the invention thatdeploy louvers 600. The frame 1110 is supporting a plurality of planarlight redirecting elements 1124 of louvers 600 disposed in pivotingengagement with the frame 1110 to rotate about a primary axis 1001, witheach louver 600 being operative to rotate about a secondary axis 1002 atthe point of the connection to the frame.

FIG. 10 is a schematic perspective view of another embodiment of theinvention in which the frame 1110 deploys tiltable louvers 600, in whicha first actuator 9001 is controlled to pivot the frame 1110 in responseto solar elevation or day, date and latitude. A second actuator 9002 isdeployed to control louver 600 tilt within the frame 1100. All of thelouvers 600 may be coupled to a common control bar 1119, which connectsto a side portion of the louver distal to the axial connection 1002. Themovement of control bar 1119 by the actuator 900 rotates each louver600. The actuator can be any form of a motor, such as a stepper motor.The first and second actuator 9001 and 9002 are responsive to acontroller 520 to change orientation in response to the changing solarelevation through the day during the entire year. The solar elevation isdetermined by a module 910. Module 910 can be operative to determine thesolar elevation by actual measurement or by calculation. For example,solar tracking is optionally by calculation from time of day, windoworientation, latitude and date, or by an optical system with positionsensitive detectors, that measure the actual solar elevation and azimuthand/or or by movement of frame and/or louver via the coupled actuatorsto optimize total light through-put from one or more remote detectors ora sampling detector that is illuminated by an additional optical elementthat is attached to move with the frame and/or louver(s). It isanticipated that the controller or module are a microprocessor orreceive commands based on calculations from a microprocessor that isconnected by a wired or wireless connection, such as a smartphone ortablet computer device.

FIG. 11 illustrates the frame 1110 supporting a rigid and optionallymonolithic panel 1200 or panel formed of tiles 1121 in which the frame1110 is tilted by an actuator 9001 in response to solar elevation orday, date and latitude as described with respect to FIG. 10.

FIG. 12 illustrates a frame 1110 as mounted to a building structure asin FIG. 7A, but showing the first and second actuator 9001 and 9002 areresponsive to a controller 520 to change orientation in response to thechanging solar elevation through the day and yearly cycles. The firstactuator 9001 is mounted on the stand-off 1140 adjacent pivot hinge1130, whereas second actuator 9002 is mounted on the frame 1110 tocouple to a first sub-set of louvers 601 above the pivot axle 1130, anda second sub-set of louvers 602 disposed below the first sub-set oflouvers 601.

As illustrated in perspective view in FIG. 13, one embodiment of thelouver or slat 600 is transparent rigid planar support surface in arectangular shape having opposing faces, and a set of orthogonal frontand rear faces and left and right sides, in which the faces are longerthan the side. The edge of the louver 600 can be coupled to end cap 605,and each of the two opposing end caps 605 preferably has an axles 606that engages the frame 1110 to provide a means for tilting the louver600. The end cap 606 may provide other projections that enable thetilting about the axis of axle 606. The front face of the louver 600 isthe light transmitting portion 1125, whereas light re-directing portion1120 is preferably internal. The rear face, opposite the front face isalso light transmitting. However, in certain construction of the slat orlouver 600 the rear face can be a portion of the light re-directingstructure 1120, such as in the embodiment s of FIGS. 18B, 19 and 20A-C.

FIG. 14 is a schematic cross-sectional elevation of a first preferredembodiment of a light re-directing structure 1120 in a louver panel 600of FIG. 13, which deploy macro spaced TIR surfaces, which preferablyhave a small radius of curvature at the corners to minimize glare. TIRsurface 110 a and 110 b are on opposing sides of the optical elements110, which have four corners 110 c, with the TIR surface being definedby the gap, g, between each adjacent optical element 110. The opticalelements 110 are preferably attached with adhesive layers 130 and 130′to an optical quality transparent substrate and superstrate 120 and120′. The pitch between gaps is preferably about 0.5 mm or greater. Theaspect ratio of the optical elements is selected to avoid leakage thatis rays traveling at too shallow an angle to impinge on the surface 110a for TIR, depending on the anticipated range of exposure angles to thesun, as well as to avoid double reflections. A useful compromise in theapplication with the tilting frame 110 is between about 1.7 to 3, andmore preferably about 1.8 to 2.2 and most preferably about 2.

Preferably, the substrate and superstrate 120 and 120′ have the samethickness to create a vertically symmetric structure to precludedistortion from thermal expansion. Glare is minimized by deployingoptical elements 110 with a pitch between elements 110 of at least about0.5 mm, and more preferably greater than 1 mm, with corners 110 c havinga radius of curvature of less than 2% of the optical element spacing orpitch, that is the element width plus the thickness of the gap 115, andmore preferably less than 1.0% of the element spacing or pitch, but mostpreferably less than 0.5% of the element spacing or pitch.Alternatively, in the embodiment deploying parallel sided opticalelements 110 at least some of the otherwise TIR provided by gap 115 canbe metalized and need not depend on the gap to provide reflection.

It should be appreciated that other light re-directing structure thatoperate by total internal reflection, such as those illustrated in FIG.18-21B also benefit by having the preferred and more preferred ranges ofpitch. When the pitch between the closest spaced apart lightre-directing optical surface is greater than 0.5 mm, and more preferably1.0 mm, column glare is substantially reduced or eliminated. Inparticular it should be noted that the light re-directing structure ofFIGS. 15 to 21B all have some faceted surfaces that are disposed at anoblique angle with respect to the planar optical panel 1120, but mayalso have some planar regions between these faceted surfaces, such as inFIGS. 19 and 18A and B. However, the light redirecting structure in FIG.20A-20B also include relatively wide planar regions 1129, that is forexample greater than about 1 mm, but more preferably about 3-15 mm, andare separated by faceted regions 1127. The bands of faceted regions 1127without some intervening bands of planar region between each facet willgenerally not provide see-through visibility, however when the widerplanar regions are as little as about 3-5% of the total area (of theplanar bands and faceted bands lacking planar regions), then a usefullevel of see through visibility can be achieved. Such see-throughvisibility is helpful for persons residing inside the structure toresolve the shape and placement of objects in the exterior environment,such as trees, buildings, vehicles, hills, mountains, clouds and thelike. It should be appreciated that the bands of planar see-throughregions 1126 are wider than the spacing of adjacent light redirectelements, such as the facets in the light re-directing regions 1127. Thelight redirecting regions 1127, are preferably transparent and re-directlight by total internal reflection, such as off tilted facets orsurfaces like 110 a in FIG. 14 that are parallel to the adjacent surface110 b, and transverse to the front of panel 1120.

The optical panels 1120 or louvers 600 that deploy the optical structureon the face of film 1128 is more preferred over other embodimentsbecause it can be produced in the form of larger panels, tiles, slats orhigh aspect ratio louvers using conventional metal molds that do notrequired diamond machining. Such molds can be used in high rateproduction processes, such as compression and injection molding, and canhave a long useful life. Further, when the planar regions 1125′ are 2-20mm wide it is easier to achieve some optical absorption by paintingtinted coating on then or patterns of smaller opaque dark dots, such asby silk screening. A none limiting example of a preferred embodiment ofthe optical panel 1120 in FIGS. 20A and B and 21B would be the planarregions 1125′ being a band with a width of about 1 mm and the non-planaror faceted regions 1127 being a band with a width of about 11 mm, for atotal pitch of 11 mm, and about 9% of the area being planar bands 1125′.

When the panels 1120 have some optical absorption it is preferable inmany situation to provide total transmission of from about 50 to 90%,with the highest transmission being about 92% when Fresnel reflectionsfrom the front and back surface are accounted for.

It should be noted that another benefit of rotating the frame and thelouvers is that the frame rotation captures more light, but in the caseof rectangular optical elements 110 of FIG. 14-17 which providesee-through visibility (in the direction of arrow 1 as will be describedin further detail below) the louvers 600 can then be tilted so that theTIR surfaces 110 a are disposed closer to lateral to optimize seethrough visibility for a viewer looking outward in the direction normalto the glazing surface 15.

As is also illustrated in FIG. 14-19, in a more preferred embodiment ofthe invention either the optical panel 1120, tiles 1121 or the louvers600 have an external or internal Infrared light (IR) reflective member,which is optionally an IR reflective coating 1201. The IR reflectinglayer is preferably a multi-layer thin film coating 1201 that reflectsIR light (illustrated as reflected ray 13) and transmit visual light ray10 into the optical elements 110, in which the TIR re-directed visiblelight exits as reflected ray 11 toward the plane of the pivot mounts(i.e. toward the window 15 or building wall 17) to be scattered off theceiling 20. The lamination of the substrate 120 and optical adhesive130, along with the multi-layer thin film coating 1201 forms the lighttransmitting portion 1125. The IR reflecting material can be monolithic,or any of the multi-layered films are optionally metal and/or dielectricmirrors, or

IR reflecting coatings 1201 are disclosed in, among others, thefollowing US patents and published US patent applications:US2010/0132756A1; U.S. Pat. Nos. 7,709,095B2; 7,508,586B2; 8,728,636B2;8,404,303B2; 7,824,777B2 and 7,964,285B2, which are incorporated hereinby reference.

Further, a more preferred embodiment of the louvers 600 confersadditional benefits. In particular, with respect to the embodiment ofFIG. 15-17 a black absorbing layer 405 is provided on a surface 110 b ofeach optical element 110. While the layer 405 will not interfere withsee through visibility of louvers 600 in a direction parallel to surface110 a and 110 b (ray 1), any rays of light incident on layer 405 will beabsorbed. In normal use (FIG. 15-16), the louvers 600 are rotated sothat layer 405 of each optical element 110 is disposed on the upperface. As the TIR of incident sunlight occurs on the opposing or lowersurface, the absorbing layer 405 only absorbs visible light at highazimuthal angles that would undergo a second reflection. Even if thelouvers 600 are moderately tilted the absorbing layer will be a smallfraction of the lateral projected area and not interfere with visibilityof external objects to viewers inside the building. However, in apreferred embodiment the louvers 600 are rotated 180 degrees, as shownin FIG. 17, the sunlight is absorbed and not re-directed into theinterior. This is like turning the light off, although see-throughfunction will be maintained.

FIG. 15 is a schematic cross-sectional elevation of an alternativeembodiment of a light re-directing structure in a louver panel 600 ofFIG. 11 deploying macro optical elements 110 with alternating blackenedfaces 110 b formed by coating or depositing an absorbing layer 405thereon to provide asymmetrical light re-direction. blackened faces 110b are disposed below the opposing face 110 a of each optical element110, so that any potential multiple reflections (illustrated as raysegment 10 c′ in FIG. 15) are absorbed, and do not cause glare from raysthat would otherwise be re-directed back in the same direction asincident solar rays 10, that is back down toward the interior floor.

FIG. 16 illustrates a more preferred embodiment of louvers 600 with thealternating absorbing layers 405 on adjacent optical elements. The IRreflecting layers 1205 and 1205′ are disposed on both sides of thelouver 600 so that IR radiation is reflected away from the building inboth the conventional orientation of FIGS. 16-17, and the absorbinginverted orientation of FIG. 18.

Another benefit of tilting the louvers 600 is to position the IRrejecting coating 1201 at the optimum angle for IR reflectivity, albeitat a potential compromise in the efficiency or location of lightre-direction within the room. However, It should be appreciated themulti-layer thin film coating 1201 can be tuned to have optimumefficiency at a given IR wavelength and more specifically, over theprominent wavelengths of solar IR emission, at a particular range ofangle of incidence, to optionally correspond with the optimum for lightre-direction.

It should be noted that the substrate for the IR reflective coatings1201 is optionally disposed on flexible film 120 having an opticalquality adhesive 130 on the opposing sides. Alternatively, the substrate120 for the IR reflective coatings 1201 can be rigid or flexiblematerials, such as glass or plastic plate or sheets. Preferably, themulti-layer IR reflective coating 1201 is disposed on at least one ofthe substrate and superstrate 120 and 120′, with the IR reflectivecoating side attached with adhesive layers 130 and 130′ respectively tothe optical elements 110.

Further, various embodiments may also provide exterior glazingprotection in storms or high winds, such as by deploying impactresistant plastic panels or louvers when the frame is tilted to thewindow and louvers are vertical. Multilayer polymer films that are IRreflectors are known, and polymeric substrates, such as polyester films,can be coated with thin film multi-layer coatings 1201 to provide impactresistant plastic for the optical panels 1120 and/or louvers 600.

FIG. 16A-17 illustrate methods of using a more preferred embodiment ofthe louver 600 of FIG. 16A or FIG. 16B as orientated in FIG. 15. In FIG.17, the louvers 600 are rotated through 180 degrees with respect to FIG.15. In the orientation of FIG. 17, high angle sunlight is absorbed bylayers 405, but light from low angles to the glazing (that is closer tothe surface normal to the glazing) whether diffuse or directional,enters the structure so the inhabitants have the benefit of being ableto see through the building exterior via the windows 15, and can thusvisualize the external view of the surroundings. The IR reflectingcoating 1201 and 1201′ are on opposing faces of the louver 600 in FIGS.16A and 16B so that IR radiation is reflected in either orientation.That is, when the louvers are inverted, the IR radiation is reflectedbefore entering the portion of the louver with the spaced apartreflective surface. When the louvers are upright and the frame ispivoted to optimize the amount of sunlight that enters the structure,the other IR reflecting coating or layers are operative to reflect theIR radiation before it enter the portion of the louver with the spacedapart reflective surface. It should also be noted that in FIG. 16A, theIR reflector layer 1201 and 1201′ can be on substrates that arelaminated with the optical adhesive 130 and 130′ between the substrates120 and 120′ to opposing sides of the optical elements 110. The spacedapart IR reflector layer 1201 and 1201′ can be on substrates that arelaminated or otherwise attached to any other light re-redirectingstructure disclosed in this application, or known in the prior art. Thiscan be achieved in the form of optical panels, tiles that form panels orlouvers by laminating an optical re-directing film to a panel of forexample tempered glass or rigid plastic or laminated glass having an IRreflective coating, and then laminated either another panel of temperedglass having an IR reflective coating, as well as a flexible transparentfilm having such an IR reflective coating. The tempered glass orlaminated glass would provide the rigidity of the optical panel, whilethe laminated light re-directing and IR reflective films can provideadditional strength by safely holding any form of glass together shouldit break.

The embodiments of FIG. 16A-17 can also be provided without the IRrejecting layers, such as for example when building windows 15 alreadyhave IR reflecting coating or layers. It should be appreciated that theembodiments of FIG. 16A-17 can also be deployed to avoid the need forthe glass window 15 to use such an IR reflecting layer or structure, andreduce costs. This is particular the case as shown in FIG. 6 whenoptical panel 1120 and frame are used only in the upper or clerestoryportion 15 u of the window 15. As this smaller optical panel 1120 may insome locations be sufficient to reject a sufficient amount of IRradiation, this may avoid the need to use IR reflective material or as acomponent of the floor to ceiling window 15.

FIGS. 18A and 18B illustrate an alternative embodiment of the louver 600or panel 1120 that is supported directly by the frame 1110 that deploysa light re-directing structure 1020 with grooves to form TIR surfaces.The efficiency is limited by the groove width required for fabrication.The structure 1020 is laminated to a support 120 having either anexternal or internal IR reflecting coating 1201.

FIG. 19 illustrates another embodiment of the invention in which planarlight transmitting member panel 1120 has one light transmitting portion1125 optionally a relatively thick rigid glass or plastic pane havingthe IR reflecting coating 1201 on an internal surface being attached tothe light re-directing member 1120. The structure of any of theembodiments that can be used to form full panels 1120 and an assembly ofsmaller tile panels that are supported by frame 1110, but can also beused to provide rotatable louvers 600. The light redirecting portion ofpanel 1120 can be the high efficiency see-through assemblies of FIG.14-17, or the other light re-directing structures with angled groove ofFIG. 18A-19. The IR reflecting coating 1201 can be laminated internallyas shown in FIG. 19 in which the coating 1201 is on a rigid panel orlouver slat 600 and the 1120 is attached to the IR reflecting coating1201 with a transparent or partially absorbing pressure sensitiveadhesive.

FIG. 20A-21B illustrate alternative preferred embodiments of an opticalpanel 1120 (or louver 600) in which a light transmitting member 1125region has an alternating patterns or bands of see-through or visibleplano portions 1125′ of width Wp with bands 1127 of intervening lightre-directing elements 1124 that have mainly facets 2025 and grooved 1125or are otherwise prismatic, and hence do not provide see throughvisibility of the exterior to inhabitants of the structure. The facetscan be disposed at various oblique angles to the plain of the regions1125′. These bands 1127 of the facets 2025 have a width Wg. The ratio ofheight or area of the grooved/plano bands is preferably greater thanone, and more preferably greater than 2/1, and most preferably can behigher than 10/1, such as 20/1 or 25/1. The spacing or pitch of theplano elements 1125′ can be varied to provide an optimum see throughvisibility appropriate to the ratio of the grooved/plano elements.Generally the plano areas 1125′ may have a width that is at least about1 mm, but less than about 25 mm. As the plano portions 1125′ provide seethrough visibility, and optionally have reduced visible lighttransmission (relative to the grooved or prismatic elements 1120) toavoid the strong glare of direct sunlight, such as in early morning orlate afternoon hours at east and west facing orientations. Thetransmission in the plano area 1125′ can be controlled by an area ofcontinuous optical density or by a printed pattern array 1129 of opaqueor partially transparent material, to provide between about 92% and 1%total transmission. The transmission is more preferably 90% to 30% andmost preferably between about 90% to about 50% transmission. It may bemore desirable to provide reduced transmission of the plano regions1125′ when extraneously external objects are likely to redirect sunlightdirectly through them, such as reflections off metallic structures,traffic signs or signals and water. However, depending on the width orpitch of the non-planar light re-directing regions 1127, relative to thewidth of the plano regions 1125′, if the non-planar regions 1127 provideno light absorption, then it may be desirable to further decrease thetotal transmission of the plano regions 1125 to between about 10% to70%.

FIG. 20A-B also schematically illustrate an optical light redirectingelements 1124 that can have a sufficient thickness to be self supportingand comprise the optical panel 1120. It should be appreciated thatoptical properties of the simple optical panel 1120 with transmittingregion 1125′ in FIG. 20A-B can be achieved as shown in FIG. 21A bylaminating the strips or tapes prismatic or grooved material 2124 to arigid transmitting substrate 1125, such as tempered glass with gaps 2125between them. Alternatively, as shown in FIG. 21B, the opticalproperties can be obtained by laminating a prefabricated film 2127 ontoa substantially equivalent expanse such a light transmitting substrate1125. The prefabricated film 2127 with the same structure non-planooptical structure of the embodiment of FIG. 20A that also has wide planoregion 1125′ separated from the light redirecting region 1127 having thefacets 2025 and grooves 2024 as light redirecting elements 1124. Thegrooves 2024 defined by adjacent facets 2025 in the embodiment of FIG.20A-B, FIGS. 21A and 21B can have any spacing, but a spacing of greaterthan about 0.5 mm is preferred to avoid glare and simplify fabrication.Alternatively, louvers 600 can have light re-directing structures 1124of the optical panel 1120 in FIGS. 20A-B or 21A and 21B. It should beappreciated that an alternative embodiment may also include the IRrejecting coating or elements 1201, or equivalent, which is shown inFIG. 21B as being disposed between the substrate 1125 and theprefabricated film 1128. The plano areas 1125′ (FIG. 20A or FIG. 21B)are preferably raised above the peak of the facets that define thegrooves for lamination to the substrate 1125 as shown in FIG. 20B, suchas with a pressure sensitive adhesive 1126. The adhesive 1126 or thesubstrate 1125 may contain an optically absorbing filler or selectivelyapplied coating to limit the continuous optical density in the planoregions 112′5, or a printed pattern array 1129 of opaque or partiallytransparent material (as shown in FIG. 20A), to provide between about100% and ˜1% transmission. The transmission is more preferably 10% to50% and most preferably between about 10% to about 25% transmission.

It should be appreciated that the embodiments of FIG. 20A-B, FIGS. 21Aand 21B deploying films 2124 and 2127 be beneficially used when applieddirectly to, in front of or behind window glazing 15, and do not need tobe applied on an optical panel 1120 on an exterior frame 1110 that ispivoted away from the window 15.

In a further embodiment, illustrated in FIG. 22, of the invention thelouvers 600 can have multilayer coating 1503 that transmits infrared(IR) radiation but reflects visible light, commonly referred to as a“cold mirror”. When deployed opposite the absorbing layer 405, such acoating 1503 would re-direct only the visible light into the room (ray11), and the IR radiation rejecting element 1503 would transmit the IRradiation (ray 12) to be absorbed either by a back surface coating 405on the reverse surface of the plano-plano optical element, or in thealternative via a sufficiently rigid absorbing substrate having the coldmirror coating disposed directly thereof.

Optionally, the back surface coating 405 can be a partially transparentmaterial, to provide between about 100% and ˜1% transmission. Thetransmission is more preferably 10% to 50% and most preferably betweenabout 10% to about 25% transmission. The louvers 600 would not need tohave an additional light redirection structure when the coating 1203 isthe upper surface of the louver. When the louver 600 are orientedvertically (broken lines), a partially transmission of the layer 405would offer a measure of privacy to the interior as well, as see throughvisibility. Layer 405 can have discrete dots, lines or other patterns ofabsorbing material to control the transmission level, as well as adispersed or dissolvent dye type absorber to have essentially uniformspatial transmission levels.

FIG. 23A-B illustrate another embodiment of the invention in which thelouvers 600 are disposed to run vertically in the frame 1110, so thatthey have a rotation axis 1002 disposed orthogonal to the tilt axis 1001of the frame. The frame 1110 and louvers 600 can be rotated by thecontrol system generally described with respect to FIG. 10 and FIG. 11.

FIG. 24A-C illustrate an embodiment of the invention in which the frame1100 is operative to rotate in the vertical plane thereof, as well astilt away from the window as shown in other embodiments. FIG. 24A showsthe frame 1110 upright, that is with sides vertical, whereas FIGS. 24Band 24C shows the frame 1110 rotated to the left and right respectively.The rotation of the frame 1110 allows for optimal collection andre-direction of sunlight as the sun moves from east to west and changeselevation and azimuthal angle during the day. The rotation of the frame1110 is preferably accomplished by the opposing standoff 1140 onopposite sides of the frame 1110 having a distal end adjustable coupledto the wall in a curvilinear track 1141 that receives a curvilinearrails 1142. The curvilinear rails 1142 support the standoff 1140. Therails 1142 can rotate clockwise and counterclockwise in the fixed track1141, and at least one of the rails 1142 is preferably driven by astepper motor type actuator 9003 that is responsive to a controller 520to change orientation in response to the changing solar elevationthrough the day and yearly cycles. As the rail 1142 is superimposed overthe track 1141 in the vertical position of the frame 1110 in FIG. 24A,the track 1141 is not visible in this view until the stepper motor 9003,or the equivalent drive means, has rotated the frame 1110 as shown inFIGS. 24B and 24C. Frame 1110 may contain multiple louvers 600 that arerotated about axis 1002, by actuator 9002, and the frame 1110 is alsopreferably rotated away from the plane of the window by actuator 9001which acts to rotate the frame 1110 with respect to axis 1001, that isassociated with pivot assembly 1130, as illustrated in FIG. 12.

It should be appreciated that in any of the above embodiments thelouvers 600 and panel 1120 can be on glass or polymeric substrates, andlaminates of glass and polymer layers. Such polymeric layers areattractive for metal and dielectric mirrors, as the cost is much lessthan glass and the weight is reduced.

It should be appreciated that the embodiments wherein a controller isoperative to pivot or rotate the louvers 600 and/or the frame 1110 inresponse to the movement of the sun, this sun tracking can be used toincrease the available sunlight in the interior and/or control where thesunlight impinges on the walls or ceiling of the adjacent interior room.It should be understood that by tracking a trajectory of the sun we meanrotating one or more of the axis of the louvers 600 and/or frame 1110 tomodify the interior illumination by some amount with respect to theinterior illumination that would occur by light re-direction throughsome portion of the day if the louvers 600 or frame 1110 was static.Further, it should be understood that the controller in the variousembodiment can be programmed to be operative to track the sun in adifferent manner through the day, year or season, for example byoptimizing total interior light during some hours, while during otherhours projecting the sun toward different regions of the interior orkeeping the sun light re-directed to different or the same portions ofthe day as the sun moves. It should be appreciated that some embodimentswill provide a greater extent of the ability to track the sun throughoutthe day than others, and selectively modify the interior illuminationrelative to a static panel 1110.

While the invention has been described in connection with a preferredembodiment, it is not intended to limit the scope of the invention tothe particular form set forth, but on the contrary, it is intended tocover such alternatives, modifications, and equivalents as may be withinthe spirit and scope of the invention as defined by the appended claims.

I claim:
 1. An apparatus for exterior light control, the apparatuscomprising: a) a first and second elongated supporting member, eachbeing spaced apart from the other with a principle axis of each memberhaving a portion disposed in the same direction as the other to define afirst plane, b) one or more planar optical panels attached at opposingsides to the portion of each of the first and second elongatedsupporting member to dispose the one or more planar optical panels inthe first plane, c) a pair of pivoting brackets, each bracket having; i)a means for vertical surface mounting to a second plane; and ii) apivoting coupling to the first and second elongated supporting membersthat is operative for adjustably disposing the one or more planaroptical panels between a positive and negative orientation with respectto the second plane, d) wherein the one or more planar optical panelscomprise a plurality of reflective elements that are operative toredirect incident light via transmission through the planar opticalpanel toward the second plane.
 2. The apparatus for exterior lightcontrol according to claim 1 wherein the reflective optical elementsre-direct light by total internal reflection.
 3. The apparatus forexterior light control according to claim 2 wherein the optical panelcomprises a plurality of louvers.
 4. The apparatus for exterior lightcontrol according to claim 3 wherein the apparatus further comprises asecond optical panel having at least one Infrared reflecting layer thatis disposed parallel to the planar optical panel in which the planaroptical panel is operative to absorb light incident at a direction abovea normal direction in a first orientation and re-direct light incidentat a direction above a normal direction in a second orientation in whichthe louvers are inverted from the first orientation.
 5. The apparatusfor exterior light control according to claim 3 wherein the louvers thatprovide the planar optical panel are disposed between two reflectivelayers on opposing sides of the planar optical panel.
 6. The apparatusfor exterior light control according to claim 3 wherein the louverscomprise a plurality of alternating bands of adjacent plano see-throughregions and light redirecting regions wherein the bands extend in thedirection of the louvers and transverse to the elongated supportingmembers.
 7. The apparatus for exterior light control according to claim3 wherein the louvers are disposed with a primary axis that extends inthe same direction as the first and second elongated supporting membersand the louvers are coupled to the first and second supporting elongatedmembers to rotate about the primary axis.
 8. The apparatus for exteriorlight control according to claim 3 wherein the louvers are operative tobe independently rotated about a primary axis independent of a pivotingmovement of the planar optical panel between a positive and negativeorientation with respect to a second plane.
 9. The apparatus forexterior light control according to claim 1 wherein the reflectiveoptical elements re-direct light by total internal reflection and have aperiodic pitch that is greater than at least about 500 microns.
 10. Theapparatus for exterior light control according to claim 3 furthercomprising a control system that is operative to pivot at least one ofthe louvers and the one or more planar optical panels to follow atrajectory of the sun.
 11. The apparatus for exterior light controlaccording to claim 1 and further comprising a means for rotation of thepair of pivoting bracket about an axis that is disposed normal to thesecond plane and midway between the pivoting brackets.
 12. The apparatusfor exterior light control according to claim 1 wherein the pivotbrackets are connected at opposing sides of the planar optical panel ata mid-point between each of the first and second elongated supportingmembers.
 13. The apparatus for exterior light control according to claim12 wherein the pivot brackets have a length that is greater than halfthe length of the first and second elongated supporting members forrotating the one or more optical panels from an upright to an invertedposition without contacting the second plane.
 14. The apparatus forexterior light control according to claim 1 and further comprising ameans to reflect infrared radiation.
 15. The apparatus for exteriorlight control according to claim 11 further comprising a control systemthat is operative to rotate the one or more planar optical panels tofollow a trajectory of the sun.
 16. The apparatus for exterior lightcontrol according to claim 1 further comprising a control system that isoperative to pivot the one or more planar optical panels to follow atrajectory of the sun.
 17. A building structure comprising: a) aplurality of exterior vertical walls, at least one wall having at leastone penetration covered by a glazing panel, b) an apparatus for interiorredirection of exterior light within the building structure thatcomprises a first and a second elongated supporting member, each memberbeing spaced apart from the other with a principle axis of each memberhaving a portion disposed in the same direction as the other to define afirst plane, c) one or more planar optical panels attached at opposingsides to the portion of each of the first and the second elongatedsupporting member to dispose the planar optical panel in the firstplane, d) a pair of pivoting brackets, each bracket of the pair beingcoupled at a distal end to the exterior vertical wall of the building onan opposing side of the at least one penetration covered by the glazingpanel and having a pivoting coupling to the first and second elongatedsupporting members that is operative for adjustably disposing the planaroptical panel between a positive and negative orientation with respectto the exterior vertical wall of the building, in which the planaroptical panels comprise a plurality of reflective elements that areoperative to redirect incident light via transmission through the planaroptical panel toward the second plane and the planar optical panel isdisposed exterior to the glazing panel.
 18. The building structureaccording to claim 17 wherein the pivoting brackets are connected atopposing sides of each of the one or more planar optical panel at amid-point between each of the first and second elongated supportingmembers.
 19. The building structure according to claim 17 wherein thepivoting brackets have a length that is greater than half the length ofthe first and second elongated supporting members for rotating the oneor more optical panels from an upright to an inverted position withoutcontacting the exterior vertical wall of the building.
 20. The buildingstructure according to claim 17 wherein the pivoting brackets arecoupled to the opposing sides of each of the one or more planar opticalpanels via each of the first and second elongated supporting members todispose each of the pivoting coupling with a common pivot axis thatextends through the first plane.
 21. The building structure according toclaim 17 wherein the pivot brackets are coupled to the opposing sides ofeach of the one or more planar optical panels via each of the first andsecond elongated supporting members to dispose the pivoting couplingwith a common pivot axis that is between an upper and lower end of thepanel and a mid-point of the panel that is between the upper and lowerend.
 22. An apparatus for re-directing exterior light within a building,the apparatus comprising: a) a first and a second elongated supportingmember, each being spaced apart from the other with a principle axis ofeach member having a portion disposed in the same direction as the otherto define a first plane, b) one or more planar optical panels, eachattached at opposing sides thereof to the portion of the first and thesecond elongated supporting member to dispose the planar optical panelin the a second plane that is one of coincident with and parallel to thefirst plane, c) a pair of pivoting brackets, each bracket having; I) ameans for vertical surface mounting to a second vertical plane on anexterior of a building; and II) a pivoting coupling to the first andsecond elongated supporting members that is operative for adjustablydisposing each of the one or more planar optical panels between apositive and negative orientation with respect to the second verticalplane, d) wherein the one or more planar optical panels comprise aplurality of reflective elements that are operative to redirect incidentlight via transmission through the planar optical panel toward thesecond plane.
 23. The apparatus for re-directing exterior light within abuilding according to claim 22 wherein the reflective elements of theone or more planar optical panels are spaced apart reflective louvers.24. The apparatus for re-directing exterior light within a buildingaccording to claim 22 wherein the one or more planar optical panelscomprises a means to reflect infrared radiation.